Hypoparathyroidism Treatment & Management

Treatment of patients with hypoparathyroidism involves correcting the hypocalcemia by administering calcium and vitamin D. ^[4]

Recombinant human parathyroid hormone (rhPTH[1-84], Natpara) is commercially available in the United States and is indicated as an adjunct to calcium and vitamin D to control hypocalcemia in patients with hypoparathyroidism. Its approval was based on the REPLACE trial (n=134). The primary endpoint was patients who achieved a greater than 50% reduction of daily PO calcium and vitamin D from baseline while maintaining serum calcium above baseline concentrations and less than upper limits of normal at week 24. Results showed that 48 (53%) of patients in the rhPTH group achieved the primary endpoint compared with 1 (2%) patient in the placebo group (p< 0.0001). ^[18]

A prospective study by Rubin et al indicated that in patients with hypoparathyroidism, long-term, continuous therapy with rhPTH(1-84) has a good safety profile, reduces the need for supplemental calcium and calcitriol, leads to stable serum calcium concentration, and reduces urinary calcium excretion. The study included 33 patients, who underwent therapy with the hormone for up to 6 years. ^[19]

A retrospective cohort study by Rejnmark et al indicated that in patients with chronic hypoparathyroidism, those treated with rhPTH(1-84) are less likely to develop chronic kidney disease (CKD). The risk for incident CKD in adult patients who were treated with rhPTH(1-84) was, over a 5-year follow-up period, 53% lower than in individuals with chronic hypoparathyroidism who did not receive the hormone. ^[20]

Guidelines on chronic hypoparathyroidism by the European Society of Endocrinology, released in 2015, are below: ^[21]

• Consider a diagnosis of chronic hypoparathyroidism (HypoPT) in a patient with hypocalcemia and inappropriately low parathyroid hormone (PTH) levels.
• Consider genetic testing and/or family screening in a patient with HypoPT of unknown etiology.
• Treatment targeted to maintain serum calcium level (albumin adjusted total calcium or ionized calcium) in the lower part or slightly below the lower limit of the reference range (target range) is suggested, with patients being free of symptoms or signs of hypocalcemia.
• Treat patients with chronic HypoPT with symptoms of hypocalcemia and/or an albumin adjusted serum calcium level < 2.0 mmol/L (< 8.0 mg/dL/ionized serum calcium levels [S-Ca ²] < 1.00 mmol/L).
• Offer treatment to asymptomatic patients with chronic HypoPT and an albumin adjusted calcium level between 2.0 mmol/L (8.0 mg/dL/S-Ca ²⁺ 1.00 mmol/L) and the lower limit of the reference range in order to assess whether this may improve their well-being.
• Use activated vitamin D analogues plus calcium supplements in divided doses as the primary therapy.
• If activated vitamin D analogues are not available, treat with calciferol (preferentially cholecalciferol).
• Titrate activated vitamin D analogues or cholecalciferol in such a manner that patients are without symptoms of hypocalcemia and serum calcium levels are maintained within the target range.
• Provide vitamin D supplementations in a daily dose of 400–800 IU to patients treated with activated vitamin D analogues.
• In a patient with hypercalciuria, consider a reduction in calcium intake, a sodium-restricted diet, and/or treatment with a thiazide diuretic.
• In a patient with renal stones, evaluate renal stone risk factors and management according to relevant international guidelines.
• In a patient with hyperphosphatemia and/or an elevated calcium-phosphate product, consider dietary interventions and/or adjustment of treatment with calcium and vitamin D analogues.
• In a patient with hypomagnesemia, consider measures that may increase serum magnesium levels.
• The routine use of replacement therapy with PTH or PTH analogues is not recommended.

Patients undergoing parathyroidectomy for parathyroid hyperplasia are at high risk of developing permanent primary hypoparathyroidism.

Patients may be treated with an autotransplant of a segment of parathyroid gland to prevent hypoparathyroidism. ^[7] This autotransplant is usually placed subcutaneously in the forearm or in the neck. A study by Teshima et al indicated that if the parathyroid glands cannot be preserved in situ during total thyroidectomy for thyroid cancer, hypoparathyroidism can best be avoided by autotransplantation of two or more parathyroid glands. The investigators found that 33% of the patients in whom one parathyroid gland was autotransplanted developed permanent hypoparathyroidism, while none of the patients in whom two or more parathyroid glands were autotransplanted developed this condition. ^[22]

If the autotransplantation fails, patients receive the same treatment that is administered to other patients with hypoparathyroidism.

An endocrinologist should be involved in the care of all patients who have primary hypoparathyroidism or who are at risk of developing it.

A diet rich in calcium content (ie, emphasizing dairy products) is recommended for patients with primary hypoparathyroidism.

Patients with symptomatic hypocalcemia develop tetany. Otherwise, no restriction in activity for these patients is necessary.